Piston type posts are economical, while the Wedge type posts are clearly ultra-precise. Both accept the toolholders and interchange with Aloris, Dorian, and DTM Tooling A: 3” B: 4-5/8” C: 2-3/4” D: 5/8” E: 1-5/8” H: 5-9/16” R: 7-5/16” BXA Wedge Type Quick Change Tool Post for Lathe Swing 10”-15”, 250-222 For Lathe Swing 10 – 15”, BXA Quick Change Tool Post (USA STYLE). Both are precision engineered to assure repetitive accuracy Advanced design provides built-in quick tool changing versatility with positive rigidity to meet the most exacting tolerances.